The ore deposit is the concentration place of minerals in the crust. It means that in the crust Geological process It is a comprehensive geological body whose quantity and quality of useful mineral resources can be exploited and utilized under certain economic and technical conditions. [1] The ore deposit contains ores, which means that useful elements can be extracted from it under technical and economic conditions Useful components Or a mineral aggregate of useful minerals. The ore often includes Useful mineral (also known as Ore minerals ）And Gangue mineral Two types of minerals. Useful minerals are those that can provide useful elements (or Components ）Or minerals that can be directly used by themselves; Gangue minerals refer to those minerals that are useless in ores. With the development of technology and economy mineral aggregate Whether it can be used as ore can be changed, and the concept of corresponding geological ore deposit can also be changed. The content of useful elements, components or minerals in ore is called grade. The grade of metal ore refers to the content of useful metal elements or components; Nonmetal Ore grade It usually refers to the content of useful minerals or useful components. The rocks around the deposit are called surrounding rock And the rock that provides the source of ore-forming materials in the deposit is called Parent rock 。 The size, shape and occurrence depth of the deposit can vary considerably. The shape of ore body can be discontinuous vein and convex mirror, irregular block, cylinder or carrot, fissure network vein, broken rock, and disseminated body and sedimentary layer in sedimentary stratum. Little is known about the exact depth or maximum depth of deposit formation. Diamond crystals may be formed tens of kilometers deep upper mantle ； Sulfide minerals are formed hundreds to thousands of meters deep. Many deposits can be formed up to 16 km deep. The temperature and pressure of mineralization vary widely, depending on the depth of mineralization. from Magma Molten body Differentiation Formed Magmatic segregation The deposit was formed under very high temperature and pressure. The pressure temperature relationship during mineralization may be complex. hydrostatic pressure The gradient depends on the density or salt content of groundwater. Generally, 3 kg/cm2 will be added for every 30 meters of deepening (40~45 pounds/square inch will be added for every 100 meters of deepening). At the same depth, Geostatic pressure Or rock pressure is 2-3 times of hydrostatic pressure. Symbiotic order It refers to the sequence of formation of different minerals in a deposit. In the same deposit, with the change of temperature, pressure and chemical composition of ore-forming liquid, different minerals will precipitate at different times. There is not only one Hydrothermal fluid Under the metallogenic conditions of the active period, the symbiotic sequence will be further complicated. According to many Hydrothermal deposit According to the stability order of minerals, the general order of mineral deposition has been determined. The ore zoning phenomenon is related to the mineral paragenesis sequence. When the ore-forming liquid moves along the channel in the rock, it changes in temperature, pressure and chemical composition. Results During deposition Magma The enrichment of different minerals can be formed with the increase of source distance. This zoning phenomenon is common, but not always occurs in the deposit. Generally, tin, tungsten and bismuth minerals are closer to the magma source than copper minerals, while lead and zinc minerals are farther away, Natural gold 、 Natural silver And gold and silver bearing minerals, while antimony and mercury minerals are farthest from the magma source. There are many kinds of deposits State of matter It can be divided into solid deposits. Liquid and gas deposits. Solid deposits are the most widely distributed, liquid deposits include oil, hot brine and groundwater, and gas deposits include natural gas; Press Metallogenesis The deposit can be divided into Endogenetic deposit （ endogenic geological process Generate) Exogenetic deposit （ exogenic process Generation) and Metamorphic deposit （ Metamorphism And endogenetic deposits include magmatic deposits, pegmatite deposits Contact metasomatic deposit Hydrothermal deposits, exogenetic deposits include weathering deposits and sedimentary deposits, and metamorphic deposits include regional metamorphic deposits Contact metamorphic deposit and migmatized deposit ； It can be divided into metal deposits (such as gold deposits Tungsten deposit ）、 Nonmetallic deposit (e.g Fireclay 、 fluorite And energy deposits (such as oil, coal and natural gas). The types of solid deposits can also be further classified in detail according to the host rock. The concept of mineral deposit includes dual attributes of geology and economy and technology. The environmental attributes of mineral deposits are getting more and more attention. The geological attribute, economic and technical attribute and environmental attribute of the deposit are interrelated and mutually restricted, and the geological attribute is the basic attribute of the deposit; Economic and technical attributes are the main indicators to define the mineral and non mineral; The environmental attribute refers to the development under the condition of protecting the environment with less environmental impact mineral resources 。 The basic conditions for determining the deposit are:
① Useful Elements Or the mineral content should reach the minimum Mineable grade For example, the lowest minable grade of copper is 0.4%, and the lowest minable grade of iron is generally 25%. ② Ore process properties , including Useful components The occurrence state of. Such as aluminum in Nepheline and kaolinite It has a high content and can be separated, but the processing technology is complex and the cost is high, so it is generally only from bauxite Extracting aluminum from. ③ The shape and internal structure of the ore body. Useful substances in rocks are uniform distribution , or locally concentrated (e.g Lode ）It has a great impact on the difficulty and cost of mining, and therefore has an important impact on the determination of the lowest minable grade of the deposit. ④ Deposit scale 。 It refers to the reserves of mineable stones. The deposit is large in scale and the investment in mine construction is large, but the economic benefits are high.
⑤ All expenses for obtaining mineral products, including exploration, mining beneficiation , transportation, equipment, energy and water supply, labor wages and other expenses also determine the Minimum recoverable grade 。 The comprehensive analysis and evaluation of the above conditions determine the economic value of a deposit. The mineral deposit is the product of mineral enrichment to a certain extent, which exists dispersedly in nature. If the average content of iron in the crust is about 5%, the minimum recoverable grade of iron ore is 25%, and the iron must pass Geological process Only when it is enriched to more than 5 times and has a certain scale can it become a deposit. Geological process leading to high enrichment of useful elements or minerals Metallogenesis 。 The place where obvious mineralization occurs is called Mineral occurrences 。 Refractory material deposit
Such as refractory clay deposit Kyanite Ore deposit Pyrophyllite deposit 、 Silica deposit 、 Magnesite deposit and Graphite deposit Etc. ① Refractory clay deposit
mineral Industrial type branch Hard clay , high alumina clay and soft clay, which are often accompanied by the same layer or different upper and lower layers. Hard clay is manufactured Clay brick The main raw materials of kaolinite ， auxiliary mineral yes Diaspore 、 Gibbsite , Dickite 、 Illite 、 Pyrophyllite Etc. Ore quality requirements (based on clinker Al2O3 ≥ 30%, Fe2O3 ≤ 3.5%, Loss on ignition ≤15%， Fire resistance ≥1630℃。 High alumina clay It is the main raw material for manufacturing aluminum bricks. The mineral composition is mainly diaspore, and the secondary minerals are kaolinite Boehmite Etc. Ore quality requirements (based on clinker) Al2O3 ≥ 50%, Fe2O3≤2.5%，CaO≤0.8%， Loss on ignition ≤ 15%, fire resistance ≥ 1770 ℃. softness clay It is used as a binder in the refractory industry. The mineral composition is mainly kaolinite, and the secondary minerals are illite Hydromica and montmorillonite 。 Ore quality requirements (based on raw meal): Al2O3 ≥ 22%, Fe2O3 ≤ 3.5%, loss on ignition ≤ 18%, refractoriness ≥ 1580 ℃, Plasticity ≥2.5。 The deposit types mainly include Sedimentary deposit And weathered residual deposits. China is mainly produced in the Ordovician system of North China and Southwest China Unconformity In the middle Carboniferous strata on the surface, it occurs in the upper part the paleozoic era And medium Cenozoic era Formation. commonly ore deposit The top plate is straight, and the bottom plate is Paleokarst karst It has great influence and changes. The deposit scale is generally large and medium. The ore bodies occurring in sand shale and volcanic rocks are layered, stratoid and lenticular, with small changes in thickness, simple changes in ore type and grade, and their scales are generally medium and small. The deposit horizon ranges from the upper Paleozoic to the quaternary period All of them have been produced, of which the Middle Carboniferous has the greatest industrial significance, followed by the Late Carboniferous, Early Permian, Late Permian and Tertiary See Table 1 for the percentage of main mineralization periods and typical mining areas. ② Kyanite Metalloid deposit Mainly used for Unshaped refractory and refractory bricks Additives. Industrial minerals There are kyanite Sillimanite 、 Andalusite , which concentrate See Table 2 for quality requirements. Deposit types include: regional metamorphic deposit , made of high alumina Argillaceous rock It is the main type of kyanite deposits in China, occurring in layered, stratoid and lenticular forms. The ore body is generally tens to hundreds of meters long and several to tens of meters thick. The mineral content of raw ores is generally 10 to 30%, up to 80 to 90%. The scale of deposits is generally large and medium-sized. Typical deposits are in Hebei Province Xingtai Weilu kyanite ore（ Archean ）, Yinshan, Nanyang, Henan Kyanite Mines（ Proterozoic ）, Jixi Sandaogou, Heilongjiang Sillimanite Mines（ Sinian ）, Jilin Jiaohe Kyanite Mine（ permian ）Etc; In addition, contact metamorphism andalusite deposit (e.g. Beijing Zhoukou Store ）And Pegmatite deposit (e.g. Xinjiang Abundant Qibulagai kyanite ore). Pyrophyllite Is to make leaves Paraffin brick Main raw materials of. The ore quality is required to be Al2O3 ≥ 16~20%, Fe2O3≤1%，CaO<1%，MgO<1%, Fire resistance ≥1630℃。 Mainly composed of pyrophyllite and quartz form. The main deposit type in China is volcanic rock Hydrothermal alteration Deposits, distributed in Eastern China In Mesozoic intermediate acid volcanic rock belt, it is layered and large Lenticular body The ore body is generally tens to hundreds of meters long, tens to tens of meters thick, and tens to more than 200 meters deep. The chemical composition of ore is Al2O318~24%, SiO268~75%, Fe2O3 and K2O+Na2O are generally less than 1%. proved reserves It accounts for the majority of the total reserves and has good quality. typical Pyrophyllite deposit There are Emei in Fuzhou and Qingtian in Zhejiang. In addition, there are small-scale regional metamorphic deposit , such as Zhejiang Changshan Fangcun Mine. Ore is manufactured Silica brick Main raw materials of. The ore quality requirement is SiO2 ≥ 96%, Al2O3≤1.3%,CaO≤1%，Fe2O3≤1.5%， Fire resistance ≥1710℃， Water absorption ≤4%。 When Silica be used as ferrosilicon 、 Silicomanganese And other silicon alloy raw materials, the ore quality requirement is SiO2 ≥ 97%, Al2O3≤1%，CaO≤0.5%， P2O5 ≤0.03%。 Minerals are mainly composed of quartz form. The types of silica deposits in China are Sedimentary metamorphic deposit and Sedimentary deposit 。 Sedimentary metamorphic deposits mainly occur in the Precambrian, such as the Shimen mine in Liaoning. The ore body is layered, hundreds of meters long to more than 1000 meters, tens of meters thick to more than 100 meters, containing 296~99% SiO2, generally>97%, 0.14~1.5% Al2O3, generally<1%, 0.08~0.2% Fe2O3, generally<0.15%. The deposit scale is large. Sedimentary quartzite The deposit occurs in Cambrian devonian 、 permian 、 the triassic period And Jurassic, among which Devonian sandstone has the largest economic value. Other strata are generally medium and small, with many impurities and inferior quality. Manufacture various fire resistance Magnesia brick Of magnesium oxide , mainly from magnesite 。 The ore quality requirements are MgO ≥ 41% CaO≤6%，SiO2≤5%。 China is rich in magnesite resources, including Sedimentary metamorphic deposit , Sedimentation – Hydrothermal fluid Metasomatic deposit And weathering leaching Deposit. Sedimentary metamorphic deposits mainly occur in Proterozoic Metamorphic rock series China, Liaoning Great Stone Bridge Magnesite is the most famous. The ore is crystalline magnesite, which is large in scale and accounts for proved reserves most. The ore body is layered, stratoid and lenticular, with a length of 1000~5000m. Ore chemistry Components MgO35～47%。 Hydrothermal metasomatic deposit Dolostone Crystals are formed through hydrothermal metasomatism magnesite , such as Sichuan Hanyuan Guixian magnesite. The ore body is layered and lenticular, tens to hundreds of meters long and several meters to more than 100 meters thick. The chemical composition of ore is MgO33 ～ 45%, CaO2.2 ～ 16.8%, and acid unmelted material 0.06 ～ 1.38%. Weathering leaching deposit Basic rock Weathering crust Bottom of Carbonation Serpentinite In the belt, ore Aphanitic Mainly magnesite. Main Chemistry Components MgO36.7～41.4%， The ore is poor in quality and can only be used after beneficiation. Graphite is used as crucible 、 Aluminium carbon brick 、 Magnesia carbon brick 、 Mould powder Of raw materials, including Crystalline graphite and Earthy graphite Two. Graphite for crucible and brick making Fixed carbon The content of graphite used as protective slag shall be more than 85%, Fixed carbon content 30~60% is required. The main ore deposit types in China are regional metamorphic deposit , produced in Precambrian Medium – deep Metamorphic rock series Middle, such as Southeast Villa and Foling in Heilongjiang, crystalline Flake graphite Deposit. The ore contains 3~10% fixed carbon, and the higher one can reach more than 20%. This type of deposit is large in scale, good in washability, and reserves account for proved reserves The vast majority of. The second is contact thermal metamorphic deposit, which is composed of igneous rock and Coal measure strata Contact heating Metamorphism It forms graphite with small reserves, and typical deposits such as Lutang in Chenxian County, Hunan Province and Panshi in Jilin Province Graphite 。 In addition, Dolostone 、 Peridotite 、 Chromite 、 zircon 、 Bentonite It is also widely used in refractory industry. Dolomitic magnesium oxide Content is manufacturing refractory bricks Key indicators of. Peridotite is used to produce magnesium olivine Bricks and Unshaped refractory Main raw materials of. The ore quality requirement is MgO>40%, Fire resistance >1750℃。 Chromite is the main raw material for making chrome brick and chrome brick. Zircon is used to make zircon bricks and Insulating board Zircon for brick making concentrate The quality requirement is ZrO2 ≥ 65%, Al2O3 ≤ 0.5%, and the quality requirement of concentrate used as insulating board is ZrO2 ≥ 60%. Zircon concentrate in China mainly comes from Hainan Island Modern Coastal placer 。 In the metallurgical industry, other ores need to be added to adjust the pH in order to achieve the purpose of iron slag separation. This ore is called solvent. Mainly limestone and fluorite Etc. ① Limestone. It is the main raw material in flux. The metallurgical industry requires that the quality of limestone CaO ≥ 50% MgO≤3%，SiO2≤4%、S≤0.15%、P≤0.04%。
② fluorite 。 Because of its Melting temperature Low, with high activity and fluidity, it is often used in metallurgical industry to separate metal from impurities, and to remove slag desulphurization and dephosphorization Role of. Ore quality requirements CaF2 ≥ 65% SiO2≤32%、S≤0.15%、P≤0.06%。 Ore genesis is medium and low temperature Hydrothermal deposit Mainly filled vein deposits, such as Zhejiang Wuyi Mine; stay carbonate rocks It looks like metasomatism in the stone Stratiform deposit Such as Hunan Xianghuapu Shizhu Garden Etc. In recent years, massive layered structures have been found in Mogan Aobao area, Inner Mongolia Fluorite deposit , produced below permian Volcano of sedimentary rock In the carbonate rock interlayer of the system. Magma concentration
stay Basic rock In slurry apatite 、 Chromite 、 Sphene 、 rutile and Zircon etc. Accessory mineral Can crystallize first, followed by olivine and Orthopyroxene etc. silicate Minerals, others Silicate mineral The crystallization is later. Under the condition of very slow cooling, the earliest formed crystals, especially the heavy minerals such as chromite, may be formed by gravity Magma It subsides internally and enriches the deposit. Sometimes, the stress in the magma flow can extrude part of the liquid that has not been crystallized from the crystallized porridge, making it rich in ore deposits. This process is called pressure filtration. Contact metasomatism
This term refers to the relationship between surrounding rock and Intrusion Contact Metasomatism 。 In this process, the solution rich in iron and magnesium secreted by the intrusion diffuses, and calcium carbonate The rock reacts to form an aggregate of calcium magnesium silicate and oxide. During the formation of this deposit, skarn is often formed at about the same time and distributed around the deposit. Hydrothermal action
It is caused by hot water solution along its movement channel and movement section in the way of physical and chemical action Alteration 、 Metasomatism And the precipitation of minerals in the pores, such as sericitization Silicification And sulfide Mineralization Etc. Hot water solution, especially heavy brine, can dissolve metals with high concentration in it. This solution passes through Fault structure During upward movement, copper, silver and other minerals can be deposited. Sublimation
Volatilization of solid after heating. When cooled, the volatile gas can be crystalline or Amorphous And deposition, such as sulfur Sublimation Can occur in volcanic eruptions In hole 。 Sedimentation and mechanical enrichment
Sedimentation And mechanical enrichment: layered Salt deposit Is the product of sedimentation; diatomite Calcium rich limestone and some phosphate rock layers are also the products of this process. The oxides of iron and manganese formed in strata and enclosed lake basins are composed of hydroxide Oxides and carbonates formed by precipitation and subsequently transformed into iron and manganese. Other syngenetic enrichment of minerals in sediments, such as Base metal The precipitation of sulfide also belongs to sedimentation. Mechanical sedimentation is also an important agent in the formation of some types of ore deposits. Gold Platinum group metals , diamond and other precious stones cassiterite 、 rutile as well as Zircon etc. Placer deposit Are formed by mechanical deposition. They are carried by Heavy mineral Moving sand and Gravel It is enriched and formed by the mechanical action and winnowing action of. Eluvial processes and eluvial deposits
The mineral passing through the wall rock or ore deposit on or near the surface Chemical decomposition And mechanical disintegration. These include laterite Deposit bauxite Deposit Manganese oxide ore Bed and silicic acid Nickel deposit Etc. Very rich in gossan Gold ore And with Kyanite Metamorphic rock The kyanite deposit formed by weathering also belongs to the product of this process. metamorphic mineralization
Metamorphism It refers to the change of temperature, pressure and Hydrothermal fluid Under the action, its morphology changes and mineral reassembly. Under metamorphism, it can be formed in some rocks Kyanite Sillimanite Andalusite or Garnet etc. Industrial minerals 。 Under metamorphism, some metal deposits Ore structure It will also change. crustal movement It can cause strong folding of ore body and change ore structure. Metamorphism and crustal movement can also be a kind of mechanical action, which can make the sedimentary strata less enriched metal sulfide And is driven out to enrich in the low temperature and low pressure zone. 
